1. Field of the Invention
The present invention relates to a developing device that houses developer such as toner. In addition, the present invention relates to a process cartridge and an image forming device.
2. Description of the Related Art
A laser printer, for example, uses a developer to print on a recording medium (e.g., printing paper). The laser printer has a developing device. The developing device has a case main body in which an opening is formed. A developing roller is coupled with the case main body at a position that faces the opening. The developing roller is capable of rotating and supporting the developer that is housed in the case main body. The laser printer has a photoreceptor that makes contact with the developing roller. An electrostatic latent image is formed on the surface of the photoreceptor. By rotating both the developing roller and the photoreceptor while in contact with each other, the developer supported by the developing roller adheres to the electrostatic latent image on the photoreceptor In this way, the electrostatic latent image on the photoreceptor becomes visible. By transferring the developer from the photoreceptor to the recording medium, text or image is printed on the recording medium.
If the developer housed in the developing device leaks to the exterior, devices disposed at the exterior of the developing device becomes soiled. It is necessary to form a developing device from which developer cannot leak. In the technology disclosed in U.S. Pat. No. 6,336,014, an axis direction seal member is installed on the case main body. The axis direction seal member extends along the rotation axis direction of the developing roller. By placing the axis direction seal member in contact with the developing roller, the axis direction seal member creates a seal between the case main body and the developing roller. In addition, in the technology of U.S. Pat. No. 6,336,014, a side seal member is used. The side seal member makes contact with the developing roller so that developer does not leak from the end of the developing roller in the rotation axis direction. In this way, a seal is formed between the end of the developing roller in the rotation axis direction and the case main body. The axis direction seal member and the side seal member make contact with one another. In this configuration, a gap is not formed between the axis direction seal member and the side seal member, and thus developer can be prevented from leaking out from between the axis direction seal member and the side seal member
Note that in the above conventional technology, in the rotation direction of the developing roller, the upstream end of the side seal member is located upstream of a contact area between the axis direction seal member and the developing roller. In other words, the side seal member makes contact with the axis direction seal member at a position which is upstream of the contact area between the axis direction seal member and the developing roller.